The purpose of this project is to contribute to the understanding of hormone action on metabolic processes in normal breast tissue under various conditions and to understand the failure of or aberrant response to hormones by hyperplastic or neoplastic breast tissue under the same conditions. Among the topics studied are the response of mammary tissue in culture to hormones in terms of nucleic acid, protein, glycoprotein and glycosaminoglycan synthesis. The kinds of proteins made by mammary tissue from normal nonpregnant, mid-pregnant, lactating animals and by neoplastic mammary tissue are being analyzed. Response to prolactin and steroid hormones is assessed by chemical and histochemical methods. Histidine requiring mutant strains of Salmonella typhimurium are used for detecting mutagenic metabolites.